Rename one of the test files

[jeremykubica]

Rename test_spline_source.py to test_spline_model.py. The code is already in spline_model.py and uses class SplineModel so it is just the test file that is incorrectly named.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 91.50%. Comparing base (c87cfd4) to head (ab5b86b).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #427   +/-   ##
=======================================
  Coverage   91.50%   91.50%           
=======================================
  Files          53       53           
  Lines        3767     3767           
=======================================
  Hits         3447     3447           
  Misses        320      320           

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[github-actions]

Before [c87cfd4]	After [f4693c7]	Ratio	Benchmark (Parameter)
9.16±0.5ms	9.65±0.4ms	1.05	benchmarks.TimeSuite.time_evaluate_salt3_model
32.9±0.1ms	34.0±0.6ms	1.03	benchmarks.TimeSuite.time_additive_multi_model_source
19.1±0.3ms	19.7±0.4ms	1.03	benchmarks.TimeSuite.time_make_and_evaluate_static_sed
12.3±0.1μs	12.7±0.1μs	1.03	benchmarks.TimeSuite.time_sample_x1_from_hostmass
4.61±0.04ms	4.69±0.07ms	1.02	benchmarks.TimeSuite.time_lightcurve_source
19.0±0.2ms	19.2±0.3ms	1.01	benchmarks.TimeSuite.time_chained_evaluate_sed
4.97±0.1ms	5.01±0.1ms	1.01	benchmarks.TimeSuite.time_evaluate_salt3_passbands
11.0±0.1ms	11.1±0.09ms	1.01	benchmarks.TimeSuite.time_make_evaluate_static_source
47.3±0.6μs	47.7±0.5μs	1.01	benchmarks.TimeSuite.time_make_new_salt3_model
29.5±0.5μs	29.7±0.4μs	1.01	benchmarks.TimeSuite.time_make_simple_linear_wavelength_source

Click here to view all benchmarks.